15x7 or 15x8, help choosing some new wheels?

bootz · Postby **bootz** » Thu Jul 04, 2013 11:48 pm

The 15x6.5 stock combo is pretty sweet for our car.

I was thinking 15x7 would be sufficient for nat/aspirated but the 15x8 can be only 0.5 of lb heavier (6ul).

Is there any advantage to 15x8 with 205/50 tyres on the street?

Would 195/50 be undertyred on an eight inch rim, if so then 15x7 would be more sensible?

Mr nanotech · Postby **Mr nanotech** » Fri Jul 05, 2013 12:55 am

195/50 and even 195/45 are pretty tried and true on an 8" wheel but to be honest, if you can fit a 205/50, do it. If you are planning on a 6ul, you will certainly be able to fit a 205 under your guards without any modification, though it depends on tyre since some have fatter sidewalls. I find my ku36 to sit a lot squarer over the 8" wheels on my car than other tyres of seen so be mindful of tyre choice.

As for 7" vs 8", I doubt you'd see a substantial different in handling or feel if it's street dríven. Your main concern would be parking but to be honest, It doesn't make a huge difference to the heaviness of the steering or the turning circle/handling. Maybe if I was on a track doing consistant laps with one size and switched to another, could I potentially see a difference, but most will be in your head (not trying to offend, but It's the equiv of ass dyno).
I drive a decently wide tracked mx5 with 8" wheels and 205's plus flares to clear the body and don't see a big difference if any to other mx5's, even had other owners comment on that they find it hard to notice a whole lot of difference. I think a lot of that comes to wheel alignment too.

If you just want a sensible day to day setup for spirited drives, I'd go for the 7" with a 195/45 ku31 or something else available in a similar size. Being stock powered (assuming it is), you wouldn't need anything bigger or more rubber to lay to the ground. That being said, it won't hurt if you put on an 8" with a 205 either.

Basically, what I'm saying is that the choice comes down to preference. Hope I've been some help.

sailaholic · Postby **sailaholic** » Fri Jul 05, 2013 1:05 am

Just do the 8s and 205 50 of your doing 6ul. It won't hurt, it looks better (opinion) you've got more redundancy built in if you start needing more grip (ie turbo).

If you really like say the rpf1 but are concerned about it only being a 7, I wouldn't worry about it and just get them.

Sent from my GT-I9100 using Tapatalk 2

Lokiel · Postby **Lokiel** » Fri Jul 05, 2013 4:18 am

Look at your eventual goals and choose based on that.

If you want to turbocharge, the 15x8s are a better choice (Emilio from 949 Racing thinks that 15x8s and 205s are a great street combination for higher-powered cars).

If not, I'd choose the lightest rim possible.

Still can't decide - why not split it down the middle and go for a 7.5" 6UL rim?

See http://forum.miata.net/vb/showthread.php?t=390825 for comparisons.

Lokiel · Postby **Lokiel** » Fri Jul 05, 2013 5:03 am

As posted by Mr nanotech, it will depend on what tyres you intend to run too - check out the manufacturer's site and their recommended rim size.

The Hoosier site for example is quite surprising: http://www.hoosiertire.com/specmiata.htm

Their recommended rim-range for 205/50ZR15 tyres is 5.5-7.5". The 5.5" rim sounds way too small but you can see that a 7" rim is actually closer to the 7.5" upper limit so a 7" rim is acceptable here.

4sfed5 · Postby **4sfed5** » Fri Jul 12, 2013 7:58 pm

in new zealand they have brought in a rule where you can only fit tires on the "recommended wheel size" by the manufacturer, so the smallest tire you can put on a 8" is 225. 205 and 195 are illegal on a 8" wheel. which is dumb when you see that 205 tire is wider than 8" anyway.

Muzdaman · Postby **Muzdaman** » Sat Jul 13, 2013 12:03 am

^^^Thats technically true of Australia too.

15x8 will be quicker on the track, but not by a lot.

If you plan on going turbo or will hit the track get the 8s, otherwise pick what you like.

PaulF · Postby **PaulF** » Sat Jul 13, 2013 3:49 am

If you're getting 6UL's, the 8's:
-Will happily run 195's if you want (remember 8 inches is only around 200mm, and you'll never get defected for this if it is illegal)
-Have the potential to run wider tyres with more optimal performance (if your plans change down the line)
-Are barely heavier at all than 7's (and this is the case for most models of wheel)
-Look tough.

However, the 7's:
-Will definitely be legal with just about anything you consider
-Are ever so slightly lighter.

hks_kansei · Postby **hks_kansei** » Sat Jul 13, 2013 10:16 am

get 7s and put 205s on them.

tyre width + legal wheel size.

depending on the make/model/profile of tyre you can usually fit up to a 215 on a 7" wheel legally (just check with the tyre manufacturer first)

mazmad · Postby **mazmad** » Sat Jul 13, 2013 8:12 pm

Disagree with the others, hkskansei is spot on. For the street, why bother with 8s? They will make the tyres much stiffer, firmer riding, more uncomfortable. 205s on 7 inch will handle adequately and be more comfortable riding.

For the track.....no question, go the 8s, but for the road it is a nonsense.

hks_kansei · Postby **hks_kansei** » Sun Jul 14, 2013 10:48 am

mazmad wrote:Disagree with the others, hkskansei is spot on. For the street, why bother with 8s? They will make the tyres much stiffer, firmer riding, more uncomfortable. 205s on 7 inch will handle adequately and be more comfortable riding.

For the track.....no question, go the 8s, but for the road it is a nonsense.

Why thank you.

I'm actually thinking of refurbishing my set of 7s and putting 215s on them when the current tyres wear out.